Candle filter



April 23, 1957 c. PISTOR 2,789,699

' CANDLE FILTER Filed Nov. 12., 1952 2 She'ets-Sheet 1 7 la 5 Q I III a INVENTOR.

CHRIS TEL PAS TOR I ,2 z ATTORN y.

C. PISTOR CANDLE FILTER April 23, 1957 2 Sheets-Sheet 2 Filed Nov. 12, 1952 CANDLE rnrnn Christel Pistor, Drexel Hill, Pa., assignor to American Viscose Corporation, Philadelphia, Pa., a corporation of Delaware Application November 12, 1952, Serial No. 320,078

Claims. (Cl. 210-448) This invention relates to filters and more particularly to candle type filters for use in artificial yarn producing apparatus.

In the production of artificial filamentary material, a solution or melt of filament-forming material is pumped through a spinning jet containing one or more orifices into a setting medium. The diameter of the spinning orifices will vary depending upon the size of the filaments desired, but the orifices may be of a diameter as low as 0.05 to 0.1 millimeter or even less. If there are any solid impurities in the spinning solution or melt, they will tend to lodge in and clog one or more of the orifices which will result in the production of a defective yarn. It is, therefore, necessary to filter the spinning solution or melt several times to remove any solid impurities therefrom. A final filtration of the solution or melt is conducted by means of a candle filter mounted in the line leading from the spinning pump to the spinning jet.

One of the primary disadvantages of the prior art filters is that stagnant zones are formed within them due to their particular construction. Material trapped in these stagnant zones contaminates the spinning fluid and thereby affects the quality of the yarn. This result is readily seen in the spinning of viscose. When viscose becomes trapped in these stagnant zones, it becomes over-ripe and gells. As the gels build up, they frequently break out into the main stream of spinning fluid. This contamination of the spinning fluid with over-ripe gells results in either breakage of the yarn during spinning or in a low quality yarn. A yarn that has been so contaminated has low tensile strength and spotty dyeing characteristics.

By use of filters of this invention, a yarn can be produced that has uniformity in both tensile strength and dyeing characteristics while the danger of breakage during the spinning is reduced.

An object of the invention is to provide a novel and improved candle filter. A further object is to provide a candle filter wherein traps or stagnant zones are eliminated. Other objects and advantages of the invention will become apparent from the following detailed description.

The filter in brief comprises a fluid-tight housing which surrounds a filter core whereby an annular space 01' chamber is formed between the housing and core. The core has a plurality of grooves formed on and around its periphery longitudinally of the core. A filtering material is secured about the core so that all of the fluid to be filtered must pass through this material. Passages or conduits for the fluid preferably extend from one end of each groove to an axial bore in the filter core. It is essential to the construction that each groove extends to its passage or conduit and not beyond the passage. A ring or sleeve may be provided about the periphery of the core at the end of the core secured to the housing. The ring is of such shape that it forms an abutment or dam in the chamber between the core and the housing which extends from the openings of the passages or conduits at the ends of the grooves to the end of the core where the core is secured to the housing. By blocking ofi T L' nited States PatentO this part of the chamber, stagnant zones wherein viscose or other yarn spinning material might be trapped are eliminated.

The liquid to be filtered may be introduced through the axial bore of the core or to the annular space between the filter core and the housing. The fluid, if introduced into the annular space between the core and the housing, passes through a supply opening in the housing into the annular space, through the filter material, such as cloth, along the grooves, into the passages or conduits at the ends of the grooves and into the bore of the filter core. The solution then travels through the bore and out through a discharge conduit. If the solution is introduced into the axial bore, the path of travel indicated above is reversed.

Although the filter will be described as a cylindrical filter it is not intended to be limitative. The invention is applicable to other shapes and types of construction such as square, hexagonal, or cylindrical cores with various shaped housings. The conduits leading into the housing may be in aligned as well as parallel or angular relationship to each other and the grooves on the surface of the core may extend axially, spirally, or both.

Preferred embodiments of the invention are illustrated in the drawings in which:

Figure l is a side elevation of one embodiment of the candle filter partly in section,

Figure 2 is a sectional view of the core of the filter of Figure 1 taken on line IIII,

Figure 3 is a developed view of the ring shown in Figures 1 and 2,

Figure 4 is a side elevation partially sectioned of a modification,

Figure 5 is a side elevation of a further modification; and

Figure 6 is a side elevational partially sectioned of still a further modification.

As shown in Figure 1, the fluid-tight housing 1 forms an annular space or chamber 2 with the filter core 3 that completely surrounds the filter core 3. At one end of the housing 1, there is a discharge or entrance pipe 4 while at the opposite end there is a plug 5 for supporting the core 3 in position within the housing 1 and for sealing that end of the housing. The plug 5 also supports an entrance or discharge pipe 6 for the fluid to be filtered. The core 3 is secured to the plug 5 in any suitable manner, preferably with a screw-type fitting 7. The core 3 is an elongated member provided with an axial inner bore 8. Longitudinal grooves 9, 9 in the core surface are of various lengths and extend longitudinally of the core around or about its periphery. Over and around the periphery of the core 3 is placed a filtering material 10 comprising one or more layers or sleeves of closely woven fabric or the like. The filtering material 10 is secured in place by clamps or cords 11 that clasp the fabric to circular grooves 12 about the periphery of the core 3. The circular grooves 12 are disposed at each end of the core 3. Passages or conduits 13, 13 extend inwardly at right angles to the axis of the core from one extreme end of each longitudinal groove 9 on the surface of the core 3 to the axial bore 8. The conduits 13, 13 thereby connect with the bore in an offset or staggered relationship which arrangement provides excellent support for the core to resist the pressure applied thereupon by the fluid to be filtered. A ring or sleeve 14 may be fitted about the periphery of the core at the end of the core 3 that is secured to the housing 1. The ring 14 occupies the space in the annular chamber 2 between the core 3 and the housing 1 and extends from the supported end of the core 3 to the edge of the outer ends or termini 17, 17 of the passageways 13, 13. The outer ends or termini 17, 17 of the passageways 13, 13 are staggered axially of the core 3 in view of the varying lengths of the grooves and therefore the end of the ring 14 extending away from the supported end of the core is correspondingly stepped in shape as shown in Figure 3 wherein the difierentlevel stepsof theflsleeve 14 are identified .asA,

IB or,,C. ,,With thisarrang'ement one-of thesteps A, B

or C extends to the edge of each outer end or terminus of theconduits ,13, 13. This stepped shaped sleeve prevents any fluidfrompassing out of the main stream offlow of the fluid-thereby preventing any of the viscose from becoming trapped and stagnating within the chamber 2. .The sleeve 14 is keyed by its key 15 to a core keyway 15' whereby the ,proper relationship is assured between the steps of the sleeve 14 and the outer ends or termini 17, 17 of thepassages or conduits 13, 13 upon assembling the filt .inone method of using this filter, a fluid passes from conduit 6 within the plug 5 into thebore 8 of thecore '3, through the passages 13, I13, and then flows alongthe grooves .9 and out through the filter material "210 and is t'finally discharged through conduit 4.

Another modification of this invention is shown in Figure 4 where passages or conduits 16 connecting the longitudinal grooves 9 with the bore 8 in the core 3 do not extend inwardly at right angles to the axis of the bore as with the embodiment described above but rather slant toward the end of the bore in communication with the conduit 6 as they extend inwardly to connect with the bore. With such angular relationship between the passageways or conduits 16, 16, the grooves 9 9 and the bore 3, the fluid flows through the passages 16, 16 with only a gradual change of direction of flow. A ring or sleeve 18 may be fitted about the periphery of the core 3 at the end of the core that is secured to the housing. The sleeve is of such a shape that it occupies the annular space or chamber between the core and the housing and extends from the outer ends or termini -17 of the passages 16, 16 in the grooves 9 to the supported end of the core. ,The sleeve has an inwardly extending radial flange 18a that extends between the core 3 and the plug 5 to enable the sleeve to be secured in place by screwing the core into the plug.

In this modification the longitudinal grooves 9, 9 are all of the same length so that outer ends or termini 17 of the passages 16, 16 in the grooves are all in a common plane transverse or perpendicular to the core. This modification has the advantage that the fluid has more of a tendency to flow along the grooves and therefore more uniformly through the filter material than when the passages are at right angles to the grooves.

Figure 5 shows a further modification of the filter. Here the longitudinal grooves 19 are not continued along the Whole length of the core but are divided so that they are in the form of two or more longitudinal grooves in linear relationship to each other in place of the one longitudinal groove. Passages or conduits 20 extend in slanting fashion as in Figure 4 from the bore to the extreme end of each groove. The passages could, of course, extend at right angles to the bore. In this system a greater amount of fluid can be passed through the core over a more uniform area than when single longitudinal grooves are used.

Figure 6 shows a further modification which is similar to that modification shown in Figure 4. One difierence here is that the grooves 9, 9 are of different lengths as with the embodiment of Figure 1. As with the embodiment of Figure 4, the passageways or conduits 16, 16 which connect the longitudinal grooves 9, 9 with the bore 8 extend angularly or on a slant from the ends of the grooves toward the end of. the bore in communication with the conduit 6 as they extend inwardly to connect with the bore. In view of the fact that the outer ends or termini 17, 17 of the conduits 16, 16 are in staggered relationship axially or" the core 3 since the grooves 9, 9 are of different lengths, additional support is thereby provided for the core 3. To provide a dam or abutment adjacent each terminus 17 of the conduits 16, 16 to prevent the fluid being filtered from flowing from the main stream, a stepped sleeve 14 having different level steps as used and described with the embodiment of Figure 1 is used with the structure of Figure 6. In every other respect, the modification shown in Figure 6 corresponds to that of Figure 4.

Several modifications of thezinvention have been shown but various other modifications of the filters illustrated and described which are within the spirit and scope-of the invention will occur to persons skilled in the art.

What is claimed is:

1. A candle filter comprising a fluid-tight housing, conduits for supplying and discharging fluid from the housing, a filter core whichhas an axial bore, the core being inside the housing and being secured thereto with its bore in communication with one of the conduits, grooves in the periphery of the core, spacedpassageways which extend .from-and connect one extreme end ofeach-of the grooves to the bore '50 that fluid may pass between the-bore and the grooves, a filtering material covering the core so that thefluidpassing.throughthe core must pass through the .filtermaterial, means for securing the filter material to the .core,:and a ring fitted about the periphery of the core at the end of the core secured to the housing, the ring occupying the space between the core and the housing and extending from the outer ends of the passageways in the grooves to the end of the core where the core is secured tothe housing.

2. Acandlefilter comprising a fluid-tight housing, con- 'duits (for supplying and discharging fluid from the housing, a vfiltercore which has an axial bore, the core being inside .thehousing and being secured thereto with its bore in communication with -one of the conduits, grooves in the periphery of the core, spacedpassageways which con- .nectone extreme-end of each ofthe grooves with the bore so .that fluid may pass between the bore and the grooves, said passageways slanting toward the end of the bore in communication with one of theconduits as the passagewaysextend inwardly to connect with the bore, a filtering material covering the core so that fluid passing through the core must pass through the filter material, means for securing the filter material to the core, a ring fitted about the periphery of the core at the end of the core secured to the housing, the ring occupying the space between the core and .the housing and extending from the outer ends of the passagewaysin the grooves to the end of the core where the core is secured to the housing, and an inwardly extending radial flange on the ring for securing the ring inplace.

'3. A candle filter comprising a fluid-tight housing, conduits for supplying and discharging fluid from the housing, .a filter core which has an axial bore, the core being inside the housing and being secured thereto with its bore in communication with one of the conduits, grooves on the periphery of the core, spaced passageways extending from one extreme end of each of the grooves to the bore at right angles to each of the grooves so that the fluid may pass between the bore and the grooves, a filtering material covering the core so that fluid passing through the core must pass through the filter material, means for securing the filter material to the core, and a stepped ring fitted about the periphery of the core at the end of the core secured to the housing, the ring occupying the space between the core and the housing and extending from the outer ends of the passageways in the grooves to the end of the core where the core is secured to the housing.

4. A candle filter comprising a fluid-tight housing, conduits for supplying and discharging fluid from the housing, a filter core which has an axial bore, the core being inside the housing and being secured thereto with its bore in communication with one of the conduits, longitudinal grooves of various lengths in the periphery of the core, spaced passageways which connect one extreme end of each of the grooves to the bore so that fluid may pass between the bore and the grooves, said passageways slanting toward the end of the bore which is in communication with one of the conduits as the passageways extend inwardly to connect with the bore, a filtering material covering the core so that fluid passing through the core must pass through the filter material, means for securing the filter material to the core, a ring fitted about the periphery of the core at the end of the core secured to the housing, the ring occupying the space between the core and the housing and extending from the outer ends of the passageways in the grooves to the end of the core where the core is secured to the housing, and an inwardly extending radial flange on the ring for securing the ring in place.

5. A candle filter comprising a fluid-tight cylindrical housing, conduits for supplying and discharging fluid from the housing, a cylindrical filter core which has an axial bore, the core being inside the housing and secured thereto with its bore in communication with one of the conduits, longitudinal grooves in the periphery of the core, spaced passageways which extend from and connect one extreme end of each of the grooves to the bore so that fluid may pass between the bore and the grooves, a filtering material covering the core so that fluid passing through the core must pass through the filter material, means for securing the filter material to the core, and a ring fitted about the periphery of the core at the end of the core secured to the housing, the ring occupying the annular space between the core and the housing and extending from the outer ends of the passageways in the grooves to the end of the core where the core is secured to the housing.

6. A filter assembly comprising a filter core having 1 an axial bore and a plurality of passageways extending radially from said bore to the periphery of the core, a housing surrounding said core and forming an annular space therebetween, filter means secured around the periphery of the core, walls defining an annular groove around the periphery of the core at axially spaced locations from the passageways, a locking ring positioned to clamp the filter into each of said grooves, and an abutment surrounding one of said locking rings and grooves and extending to a point adjacent each outer terminus of said passageways which serves as a dam to provide axially unidirectional fluid flow at each of said termini.

7. A filter assembly comprising a filter core having an axial bore and a plurality of passageways extending radially from said bore to the periphery of the core, a housing surrounding said core and forming an annular space therebetween, filter means secured around the periphery of the core, means for attaching the filter to the core at axially spaced locations from the passageways, and a sleeve mounted in the annular space over the filter and extending to a point adjacent each outer terminus of said passageways to provide axially unidirectional fluid flow at each of said termini.

8. A filter assembly in accordance with claim 7 having means for keying the sleeve to the core.

9. A filter assembly in accordance with claim 7 comprising a stepped sleeve, and radial passageways which are staggered with respect to their connection with the bore.

10. A filter assembly in accordance with claim 7 in which the sleeve has an annular retaining flange cooperating with the core.

References Cited in the file of this patent UNITED STATES PATENTS 702,382 Topham June 10, 1902 781,018 Palmer Jan. 31, 1905 1,685,775 Dreaper Oct. 2, 1928 1,811,795 Kirby June 23, 1931 2,057,814 Barrett Oct. 20, 1936 2,145,047 Goldkamp Jan. 24, 1939 2,446,979 McLellan Aug. 10, 1948 2,628,819 Parsons Feb. 17, 1953 2,666,669 Wahlin Jan. 19, 1954 FOREIGN PATENTS 499,635 France Feb. 17, 1920 344,932 Great Britain Mar. 16, 1931 376,574 Great Britain July 14, 1932 499,713 Great Britain Jan. 27, 1939 

